- BG_STOPS: +10deg #e8ddcf (morning light), +30..90deg #ffffff; night half
of the scale untouched (-4 #131a28, -12..-90 #070c14)
- drawn-plan paper vs white sky: all paper shapes now sit in one
.hp-paperg group; in daynight mode the group gets a subtle
drop-shadow so the sheet contour stays readable at high sun
(static mode and night unaffected)
- pinned colors updated: test/sun.test.mjs, demo/smoke_sun.mjs;
smoke_bg_color paperUnderneath follows the .hp-paperg wrapper
- docs/SUN.md: explicit BG_STOPS table
- demo/shot_daynight.mjs: noon/sunset/night stills of the scale
